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Papers by philippe azais

Advanced Materials, Dec 5, 2016

Laser pyrolyzed SnO2 nanoparticles with an option of nitrogen (N) doping are prepared using a cos... more Laser pyrolyzed SnO2 nanoparticles with an option of nitrogen (N) doping are prepared using a cost-effective method. The electrochemical performance of N-doped samples is tested for the first time in Li-ion batteries where the sample with 3% of N-dopant exhibits optimum performance with a capacity of 522 mAh gactive material(-1) that can be obtained at 10 A g(-1) (6.7C).

Journal of Power Sources, Dec 1, 2012

h i g h l i g h t s Low temperature electrolytes were tested with commercial 600F SC cell. Mixing... more h i g h l i g h t s Low temperature electrolytes were tested with commercial 600F SC cell. Mixing MA enlarged low temperature limit of AN-based SC cell from À40 to À55 C. High temperature performance was exemplified by floating at 2.7 V and þ60 C.

Meeting abstracts, 2013

not Available.

Defect and Diffusion Forum, Mar 1, 2011

Realites Industrielles, 2018

Meeting abstracts, Oct 19, 2021

Doping of microporous carbon by Li or K leads to an increase in the energy of adsorption of H 2 o... more Doping of microporous carbon by Li or K leads to an increase in the energy of adsorption of H 2 or D 2 molecules. Thus, the room temperature sorption capacities (at P<3 MPa) can be higher than the ones of the raw materials after slight doping. However, the maximum H 2 (or D 2) storage uptake measured at T< 77 K is lower than the one of pristine materials as the sites of adsorption are occupied by alkali ions inserted in the micropores. The microporous adsorption sites of doped single-walled carbon nanotubes, identified by neutron diffraction, are both the interstitial voids (in electric-arc or HiPCO tubes) in between the tubes and the central canals of the tubes (only in HiPCO tubes).

Solid State Nuclear Magnetic Resonance, Apr 1, 2012

Weshowthatnaturalabundance,solid-stateMAS-NMR 13 CINADEQUATEspectracanbe recorded for crystallize... more Weshowthatnaturalabundance,solid-stateMAS-NMR 13 CINADEQUATEspectracanbe recorded for crystallized C70, using the through-bond J-coupling for the magnetization transfer.TheeffectofstrongJcouplingcanbelessenedathighmagneticfields,allowing the observation of cross-peaks between close resonances. DFT calculations of the chemicalshiftsshowanexcellentagreementwiththeexperimentalvalues.Acorrelation isobservedbetweentheaverageCCCbondanglesandthe 13 Cchemicalshift,offeringa waytounderstandthedispersionof 13 Cchemicalshiftsinnanoporousactivatedcarbons intermsoflocaldeviationsfromplanarity.

HAL (Le Centre pour la Communication Scientifique Directe), Apr 10, 2011

Meeting abstracts, Jul 7, 2022

Physico-chemical modeling is considered as a very interesting way of simulating the behavior of a... more Physico-chemical modeling is considered as a very interesting way of simulating the behavior of a Li-ion battery cell by linking its internal state to its performance and aging. However, an accurate parametrization of such models is necessary for a truly representative outcome. In the case of commercial batteries, the parametrization procedure is hardly ever entirely undergone, leaving room for parameters tweaking and inaccurate simulation results. In the framework of this work, over 70% of the parameters were measured for a Samsung SDI 37Ah Li-ion prismatic battery (NMC111/Graphite) for PHEV (Plug-in Hybrid Electric Vehicle) applications. A Doyle-Fuller-Newman (DFN) Pseudo 2D model is chosen based on the work of Dufour et al.1. The major electrochemical characterization technics and measurement results for every component in the cell will be presented. The cells were opened in the ante-mortem procedure2, materials were identified, geometrical parameters were measured and samples were taken for coin-cell experiments. A small portion of the electrolyte was recovered and studied to conclude that it was made of EC-DMC-EMC at 1:1:2 portions. A similar solution was synthetized in order to conduct ionic conductivity measurements at temperatures ranging from -30 to 60°C. Samples from the separator were taken for both effective ionic conductivity and porosity measurements. The tortuosity of the electrodes was calculated via an EIS (Electrochemical Impedance Spectroscopy) with a blocking-electrodes configuration, and finally the diffusion factor in the active particles was estimated via GITT (Galvanostatic Intermittent Titration Technique) experiments. A very slow current regime was used to lithiate and de-lithiate the active materials in a half-cell experiment for electrode balancing purposes. The model was compiled using COMSOL Multiphysics 5.5, and results were compared to validation experiments conducted on the full-setup prismatic cell. The charge curve was validated under different current and power regimes at 25°C, and the Incremental Capacity (IC) curve showed a reasonable accuracy. With this in hand, the following step would be to couple this performance model to an aging model and to compare the evolution of the IC peaks with the experimental aging. References: N. Dufour, M. Chandesris, S. Geniès, M. Cugnet, and Y. Bultel, Electrochimica Acta, 272, 97–107 (2018) http://www.sciencedirect.com/science/article/pii/S0013468618307229. T. Waldmann et al., Journal of The Electrochemical Society, 163, A2149–A2164 (2016) https://doi.org/10.1149/2.1211609jes. Figure 1

Batteries, Sep 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Applied Energy, Aug 1, 2023

Materials, Aug 30, 2022

Journal of energy storage, 2021

Abstract Lithium-ion Capacitors (LiCs) have recently emerged in the market of energy storage syst... more Abstract Lithium-ion Capacitors (LiCs) have recently emerged in the market of energy storage systems as a new technology having some of the advantages of Lithium-ion Batteries (LiBs) and Supercapacitors (SCs). As an important number of commercial LiCs combine the negative electrode of LiBs with the positive electrode of SCs, the lifetime of this new technology requires an effective analysis that can underlie degradation mechanisms related to each electrode. In order to evaluate the aging behavior of LiCs, calendar accelerated aging tests were applied to eighteen cells for twenty months in a previous study. Two temperatures, 60°C and 70°C, and three storage voltage values, 2.2 V, 3.0 V and 3.8 V were used to accelerate their aging. the The lifetime of LiCs was found to be particularly dependent on the storage voltage and the degradations of the cells were most pronounced at the highest temperature, 70°C. Therefore, in the current study, post-mortem analyses are applied to three cells that aged at different storage voltage values and 70°C. Considering the same aging mechanisms at high temperatures, only one high temperature was chosen. Two main aging mechanisms were observed: the pores blocking of activated carbon at the positive electrode and the loss of lithium ions from the negative electrode of pre-lithiated graphite. Elements responsible for these degradations were different at each voltage condition. Additional mechanisms were identified such as the degradation of the electrolyte and the decomposition of the positive current collector.

Elektrotechnik Und Informationstechnik, Jun 16, 2020

Thanks to its exceptional performance in terms of high energy and power density as well as long l... more Thanks to its exceptional performance in terms of high energy and power density as well as long lifespan, the lithium-ion secondary battery is the most relevant electrochemical energy storage technology to meet the requirements for partial or full electrification of vehicles (plug-in hybrids or pure electric vehicles), and thanks to decreasing cost and ongoing technical improvements, it will maintain this role in the near to mid-term future. This study benchmarks eight different (five 21700 and three 18650 format) high-energy cylindrical cells concerning their suitability for automotive applications and aims to give a holistic overview and comparison between them. Therefore, an ante-mortem material analysis, a benchmark of electrical and thermal values as well as a cycle life study were carried out. The results show that even when applying similar concepts like Nickel-rich cathodes with graphite-based anodes, the cells show wide variations in their performance under the same test conditions.

Journal of Power Sources, Oct 1, 2013

h i g h l i g h t s Electrolytes involving functional acetate as co-solvent exhibit high performa... more h i g h l i g h t s Electrolytes involving functional acetate as co-solvent exhibit high performances for supercapacitor application. Safe electrolytes can be obtained displaying high conductivities in a large temperature range. Longer cycle life should be reached using Spiro-(1,1 0)-bipyrrolidiniumBF 4 along with the improvement at low temperature.

Electrochimica Acta, Mar 1, 2013

The performances obtained with methoxypropionitrile/ethylene carbonate mixture based electrolytes... more The performances obtained with methoxypropionitrile/ethylene carbonate mixture based electrolytes were investigated in supercapacitor application. The incorporation of methoxypropionitrile allows a good compromise between electrochemical performances and safety issue to be exhibited in a wide temperature range. This improvement is associated with the decrease of electrolyte viscosity without compromising the salt solubility and dissociation. The highest conductivity values, 20 mS cm −1 at 30 • C compared to 14 mS cm −1 in PC (propylene carbonate), were obtained with both 1 M tetraethylammonium tetrafluoroborate (TEABF 4) and spiro-(1,1)-bipyrrolidium tetrafluoroborate (SBPBF 4) salts. Bulk liquid state was conserved for these electrolytes in a wide temperature range. Then, interesting electrolyte conductivities were obtained at low temperature (5.2 mS cm −1 at −25 • C) which is twice that of PC + TEABF 4 1 M electrolyte at the same conditions. Moreover, the capacitor performance of EC/MP based electrolyte is better than PC one at room temperature.